Signaling system



Dea 5, 1939. *Y R, B HEARN 2,182,340

SIGNALING SYSTEM Filed March 3, 1938 /NVE/v TOR B. HEA RN A TTU/'NVE V Patented Dee.' 5,1939

2,182,340 f SIGNAIJNG SYSTEM Richard B. Hearn, Hollis, N. Y., assignor to Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application March 3, 1938, Serial No. 193,648

Claims. (Cl. 178-71) This invention relates to signaling systems and particularly to minute current telegraph systems either for manual or machineoperation.

The object of the invention is to achieve in- 5 creased economy and speed in operation while maintaining great reliability with inexpensive apparatus operated over lines which would be unsuitable for ordinary apparatus or alternatively would require higher grade more expensive apparatus. j I

A feature of the invention is the use ofwhat may be termed condenser type relays, that is, relays which respond* to a difference in potential rather than an electric. current and which requre for their operation only that amount of energy which may be measured by the charging current of a small condenser. By way of example, such a relay is shown herein as a crystal relay having a movable element similar in construction and operation to the motor element used by Sawyer in his Reissue Patent 26,213, December 22, 1936. In general also a relay of this nature is shown in Patent 2,166,763, issued to Warren P. Mason on Julyl 18, 1939, application Serial No. 131,160 illed March 16, 1937.

Crystalrelays of the nature hereinused prove to be extremelyl quick in action, to be reliable, to require little maintenance and to have along life. The peculiar advantage of these relays, 0- however, is that they respond to potential differences and hence their use in circuits of this nature is advantageous since their operation is not slowed up through electrical impedance nor their response limited materially by the length u or the condition of the line. .Ordinary high resistance lines or leaky conditions which on other electromagnetically operated lines would seriously interfere with the operation of the system will not here cause faulty operation and hence the cost of maintenance of the system will be lower or alternatively the provision of more expensive and more sensitive apparatus will be avoided.

The drawing consists of onel sheet containing fourgures.".

Fig. 1 is a diagram of a completed connection from one signaling station conventionally illustrated as permutation code sending and receiving means to another over their lines and a repeater at a central point;

w station circuit;

Fig. 3 is a diagram of an alternative form of a repeater at a central point; and Fig. 4 is a representation of a relay madeup of two pairs of crystals.

resistance 2| to negative battery 22.

Fig. 2 is a diagram of an alternative vform of Let us first consider Fig. 4. Here we have four pieces oi crystal preferably made of Rochelle salts and which exhibit a piezoelectric effect. Other piezoelectric bodies may be used.. These crystals I, 2, 3 and 4 areeach facedby conducting sheets 5 to I0, inclusive. The conducting sheets 5 and 1 are connected together so that when a potential is applied between conducting sheet 6 and paired sheets 5 and the crystals .Ii and 2 will be distorted so as to tend to move the m central contact Il in one direction or the other toward either Contact l2 or I3. Srly when a potential difference is placed between conducting sheet 9 and the paired sheets 8 and E9, the crystals 3 and d will be distorted so as to move the l5 central contact ll either toward contact l2, or

contact E13. All four of these crystals and their conducting sheets are rigidly mounted on base I4 so that through the distortion oi the crystals the Acentral Contact ll is rendered movable. g@

In Fig. 1 there are two such relays now identilied by their movable contacts le and i6, respectively. For clarity, however,'these relays l5 and I6 are not shown as compactly as the relay of Fig. 4.

The operation of a signaling system using relays of this nature is illustrated in Fig. l. Current will flow from positive battery il out-over the station loop throughthe resistance I6, signaling contacts I9, marking contact of relay 26, a@

At the station a'crystal relay 23 will have full positive potentialon the conducting sheet between the two crystals and will derive'a negative potential on its two outer conducting sheets over resistance 24, closed contacts I9 and thence to battery 22. This potential Vdifference on the conducting plates of the crystal relay 23 will distort the crystals in such amanner as tokeep the armature on its upper or marking contact. Similarly the lefthand pair of crystals of relay I5 will have a potential difference across their" conducting sheets so as to distort the crystals in a left-hand direction. The right-hand pair-of crystals of relay I5 will be energized by potential between ground on the two outer conducting sheets and negative battery on the armature and marking contact of relay I6. This potential will distort the crystals of the right-hand pair of relay l5 toward the right with the net resultthat the armature of relay I5 will remain on itsleft-hand or marking contact.v Relay 20 will be energized in the same manner as the right-hand pair of crystals of relayl I5 and.will maintain its armature on its upper or marking contact.

When permutation code signals are sent by.

spacing contact. At the s'ame time andin a similar manner the potential difference existing on the conducting sheets of the left-hand pair o! crystals of relay I5 will be removed and all of these conducting sheets will come to the same potential with the result that the strain on this left-hand pair of crystals will'be removed and the amature I5 will move to its right-hand or spacing contact. As armature I5 moves to its right-hand contact it changes positive battery to negative battery and since this armature is connected to the inner conducting sheets of the left-hand pair oi crystals of relay I6, it will change the direction of distortion so that now the armature of relay I6 will be pressed even more tightly to its right-hand contact. On the other hand, relay will open its contact and in a man' ner similar to that described with relation to the station circuit at the left-hand end of this figure will cause the operation of relay 26. Relay 26 performs the usual functions of a receiving relay at the other end of this line. Thus impulses created by cpening and closing a circuit through which current is flowing will create potential .differences at the far end of the line to operate a'crystal relay.

Since the operation in the reverse direction is similar in all respects it will not be further described. y 1

Fig. 2 shows an alternative form of station circuit. In this instance the crystal relay 21 is energized by potential diierence existing between ground and a"negative potential derived over the line leading through contacts -28 to a negative battery. When the circuit is broken at a relay similar to relay 20 of Fig. l, then the negative potential placed on the outer conducting plate to this relay becomes a positive potential'over the line 29 and the relay operates in the opposite direction.

If Fig. 3 is placed in the position of the corresponding circuit in Fig. 1 then in the marking condition current flows from negative battery 22 through the marking contact and armature of relay 30, lower winding of relay 3l, thence over the station circuit and back to positive battery Il.

When the contacts I9. are operated, this circuit is opened with the result that relay 3| operates its armature to its spacing contact. Crystal relay 32 which until this time has been short-circuited by the contact and armature of relay 3l now receives positive potential through the lower windinggof relay on its inner conducting sheet and nega.- tive potential over resistance 33 on its two outer conducting sheets whereupon it moves its armature from its left-hand or marking contact to its right-hand or spacing contact. Relay 26 now operates as before so that a spacing signal sent by the contacts I 9 will be recorded as a spacing signal. y

on relay 2B.

The movement of the amature of relay 32 reverses the current now in the upper winding of relay 30 so 'that even though the lower winding of relay 30 is open this relay'will maintain its armature on its marking contact.

The operation in the reverse direction is sim- I ilar in nature and will not be further' described.

What is claimed is:

l. A signaling system comprising an established Y connection from one. subscribers station Yover a subscribers loop,- another subscribers loop to another subscribers station, means at either subscribers station for interrupting the continuity of the associated subscribers loop for sending impulses to the said other subscribers station, means for translating said interruptions into potential changes and a condenser type relay com;

prising crystal elements interleaved with' conducting elements responsive to potential changes at each of said subscribers stations for receiving -said signals.

2. A signaling system comprising an established connection from one subscribers station over a subscribers loop, a repeater, another subscribers loop to another subscribers station, means at either subscribers station for interrupting the continuity of the associated subscribers loop for sending impulses to the said other subscribers station, means in said repeater for translating said interruptions into potential changes and a condenser type relay comprising crystal elements interleaved with conducting elements responsive to potential changes at each of said subscribers stations for receiving said signals.

3. A signaling system comprising an established connection from onespbscribers station over a subscribers loop, a repeater, another subs cribers loop to another subscribers station,

.means at either subscribers station for interrupting the continuity of the associated subscribers loop for sending impulses` to the said other subscribers station, an electromagnetic re- .lay in said repeater responsive to said interruptions for translating said interruptions into potential changes and a 'condenser type relay com- Drising crystal elements interleaved with conducting elements responsive to potential changes at each of said subscribers stations for receiv-i ing said signals.

4. A. signaling system comprising an establishedconnection from one subscribers station over a subscribers loop, a repeater, another subscribers loop to another subscribers means at either subscribers station for interrupting-the continuity of the associated suhscribers loop for sending impulses to the said other subscribers station, means for translat ing said interruptions into potential changes, a.

lcondenser type relay responsive to potential changes in saidrepeater for sending correspond- Aing potential changes to the said other submribers station and a condenser type relay compris- Iing crystal elements interleavedwith conducting elements responsive to "potential changes at each of said subscribers stations for receiving said signal.

5. A signaling system'according'to claim 1, wherein said condenser type relays are. constructed of Rochelle salt crystals.

* a RICHARD n nnARN. 

